Helmet adapted to its usage constraints

ABSTRACT

A helmet for sporting activities. The helmet includes an outer shell and a lower portion, the outer shell designed to be positioned on a skull, the outer shell including an upper portion to cover at least the crown portion of the skull, the material forming the upper portion having mechanical properties suitable for the upper portion to satisfy a certification standard defined for the intended use of the helmet. The lower portion is affixed to the upper portion so as to form a single unitary element, the lower portion extending continuously so as to at least partially cover the lateral portions and rear portion of the skull, the lower portion being made of a material having a different modulus of elasticity than that of the material forming the upper portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon French Patent Application No. FR 14/01016, filed Apr. 30, 2014, the disclosure of which is hereby incorporated by reference thereto in its entirety, and the priority of which is claimed under 35 U.S.C. §119.

BACKGROUND

1. Field of the Technology

The field of technology relates to a protective helmet for sporting activities. Such activities may in particular include alpine skiing, ski touring, or snowboarding. The field of technology also extends to rock climbing, mountaineering, cycling, or snowmobiling. Generally, a helmet provides head protection to protect the skull from impacts to which it may be subject when the user falls, or when an object is thrown at or received by the user.

2. Description of Background

A conventional helmet construction includes an outer shell and a cap. The outer shell is generally rigid and is made, for example, by molding/injection of a thermoplastic material such as ABS (Acrylonitrile Butadiene Styrene) or PC (polycarbonate). Typically, the cap is made of a foam material such as EPS (Expandable Polystyrene) or EPP (Expandable Polypropylene). To ensure good user comfort, the helmet is generally provided with an inner cap that can be made of foam, for example, covered with fabric. The inner cap is attached to the inside of the cap.

A helmet is designed to reduce the risk of injury in the area of the skull of the user, while having the smallest possible weight in order not to affect the comfort of the user.

To ensure the safety of users, there are several standards generally defining tests and acceptance thresholds that are applied to helmets requiring certification in a related discipline. The normative requirement may differ, depending on the sporting activity. Thus, a standard covers a specific activity. These requirements give rise to characteristics that the helmet must have to provide the required protection. For example, these characteristics correspond to properties of resistance to penetration and shock absorption in various zones of the helmet.

Thus, the standards EN 1077: 2007 (Europe) or ASTM F2040 (US) are applicable to alpine skiing and snowboarding. The standards EN 13781: 2012 (Europe) or FMVSS No. 218 (US) are applicable to snowmobiling. The standard EN 12492: 2012 (Europe) is applicable to mountaineering and climbing. The standards EN 1078: 2012 (Europe) or 16 CFR Part 1203—CPSC (US) are applicable to cycling.

The current helmets, made by injection molding, typically include an outer shell made of the same material. This construction requires using of a suitable material to pass the most severe normative constraint at the expense of other characteristics such as weight, damping efficiency, etc.

Moreover, it is difficult to design a helmet that meets requirements of both resistance to penetration and resistance to impacts, in particular while maintaining a reduced weight and a low manufacturing cost.

Further, it proves difficult to use similar helmet designs for various sporting activities, as the requirements to be met, defined in the standards, are different, for example, for alpine skiing in relation to snowmobiling.

Furthermore, because certification standards may vary depending on geographical areas, it is difficult to adapt a single helmet geometry to these various standards.

SUMMARY

The invention overcomes one or more of the foregoing disadvantages.

The invention provides an improved helmet for sporting activities.

In particular, the invention provides a helmet designed to satisfy both requirements of resistance to penetration and resistance to impacts, while maintaining a reduced weight and a low manufacturing cost.

The invention also makes it possible to use similar helmet designs and the same manufacturing tools for various helmets intended for various sporting activities, and must therefore satisfy various certification standards.

The invention thus relates to a helmet for protecting the wearer's head during participation in at least one of a plurality of sporting activities.

The helmet includes an outer shell designed to be positioned on the user's skull. The outer shell includes an upper portion for covering at least the crown portion of the skull, the material forming the upper portion having mechanical properties suitable for the upper portion to satisfy a certification standard defined for the intended use of the helmet, and a lower portion affixed to the upper portion and extending continuously so as to at least partially cover the lateral and rear portions of the skull, the lower portion being made of a material having a different modulus of elasticity than that of the material forming the upper portion. The lower portion is affixed to the upper portion to form a unified bi-injected or overmolded construction.

This design optimizes the structure of the outer shell, locally providing a reinforcement of the mechanical or damping properties, depending on the normative requirements specific to a discipline. Less biased zones having more flexible characteristics can then be obtained. The result is a lighter and less expensive helmet. Moreover, by substituting a portion of the shell of a helmet dedicated to one discipline for another portion made of a different material, one can design a helmet that meets the normative requirements of another discipline.

According to advantageous but not essential aspects of the invention, such a helmet may incorporate one or more of the following characteristics, taken in any technically feasible combination:

-   -   The material forming the upper portion has mechanical properties         suitable for the upper portion to satisfy the certification         standard for alpine skiing or snowboarding.     -   The Shore D hardness of the material forming the upper portion         is between 50 and 75.     -   The modulus of elasticity of the material forming the upper         portion is less than 1000 MPa.     -   The modulus of elasticity of the material forming the upper         portion is less than that of the material forming the lower         portion.     -   The upper portion is made of one of the following materials: PU,         PP, SBS, or SEBS.     -   The lower portion is made of one of the following materials: PU,         ABS, PP, or PC.     -   The thickness of the wall of the upper portion and/or of the         wall of the lower portion is between one and three millimeters.     -   The outer shell comprises an excess thickness in the area of a         junction zone between the upper portion and the lower portion.     -   The excess thickness projects into the inner volume of the outer         shell.     -   The thickness of the junction zone is substantially equal to the         sum of the average thicknesses of each assembled portion.     -   The width of the junction zone is less than thirty millimeters.     -   The helmet comprises a cap that is distinct from the outer         shell, the cap being attached to the inside of the outer shell.     -   The excess thickness is capable of being housed in a groove         provided in the cap.

The invention also relates to a method for manufacturing a helmet for sporting activities, including a step of attaching a lower portion to an upper portion by an overmolding process or a bi-material injection process in order to obtain an outer shell of the helmet.

BRIEF DESCRIPTION OF DRAWINGS

Other features and advantages of the invention will become apparent from the following description, provided by way of non-limiting example, with reference to the annexed drawings, in which:

FIG. 1 is a front perspective view of a helmet according to the invention;

FIG. 2 is a rear perspective view of the helmet of FIG. 1;

FIG. 3 is a perspective view of the outer shell;

FIG. 4 is a median cross-sectional view of the outer shell;

FIG. 5 is an enlarged view of detail A of FIG. 4, by which the cap has been added.

DETAILED DESCRIPTION

The following description makes use of terms such as “horizontal”, “vertical”, “longitudinal”, “transverse”, “upper”, “lower”, “top”, “bottom”, “front”, “rear”. These terms should be interpreted as relative terms with respect to a helmet worn normally, with the head upright.

FIG. 1 is a perspective view illustrating a helmet 1 for sporting activities according to an embodiment of the invention.

The helmet 1 comprises an outer shell 2 and a cap 3. The cap 3 is housed in the inner volume of the rigid shell 2. It is attached to the inner surface of the rigid shell 2. The cap 3 can be covered with an inner cap, not shown. The inner cap is made, for example, of foams surrounded by a fabric, or only made of fabrics.

The helmet 1 may also include a retention system, not shown here, including a chin strap or a headband adjustment system, for examples. See, for example, U.S. Pat. No. 7,243,378, the disclosure of which is herein incorporated by reference thereto in its entirety and particularly for the disclosure of a chin strap retention system that includes a series of flexible straps.

The helmet 1 is designed to wrap at least a portion of a skull to be protected by the helmet.

The following description defines a plurality of protection zones.

A first protection zone 211, referred to as the “crown portion” of the skull, covers the top of the skull. See FIGS. 2 and 4. The first protection zone is defined by a zone covering an upper portion of the frontal bone and an upper portion of the parietal bone.

A second protection zone 221, referred to as the “peripheral portion” of the skull, covers the lateral and rear portions of the skull. See FIGS. 2 and 4. The lateral portions are defined by a zone at least partially covering the sphenoid bone and the temporal bone. The rear portion is defined by a zone at least partially covering the occipital bone.

To ensure the desired protection, depending on the particular discipline practiced, helmets must pass specific tests defined by the standard associated with the respective discipline.

For alpine skiing and snowboarding, the helmet must pass puncture tests on the top of the skull and must have adequate damping characteristics to withstand an impact in one of the frontal, rear, lateral, and crown zones. For the resistance to impacts test, a dummy head is positioned inside the helmet, and the helmet is dropped from a predetermined height, along an orientation determined at the discretion of the laboratory. The acceleration measured in the area of the head must remain below a predetermined threshold value.

For snowmobiling, the helmet must pass puncture tests on the top of the skull and must have adequate damping characteristics to alternately withstand double frontal and lateral impacts. The puncture test is more severe than that conducted to certify an alpine ski helmet.

For mountaineering, the helmet must pass puncture tests on the top of the skull and must have adequate damping characteristics to withstand the impact of a projectile sent to the top of the skull. It should be noted that the puncture test is similar to that conducted to certify an alpine ski helmet.

For cycling, the helmet must have adequate damping characteristics to pass the specific tests. These tests are similar to those conducted certify of an alpine ski helmet.

These requirements underscore that the expected characteristics of the helmet are not necessarily consistent in all zones of the helmets and are dependent upon the discipline practiced.

Thus, the crown portion of the helmet, corresponding to the first protection zone 211, must have puncture resistance properties and damping properties. Puncture resistance is mainly provided by the outer shell. Damping is achieved by the combination of the outer shell and the cap.

Therefore, the crown portion can have mechanical properties different from that of the other portions in order to optimize the structure while respecting the normative requirements. This is what the invention provides by modifying the mechanical properties of the outer shell as a function of the protection zones.

In the exemplarily illustrated embodiment, the outer shell 2 includes an upper portion 21 designed to cover at least the first protection zone 211 and a lower portion 22 extending continuously so as to at least partially cover the second protection zone 221. Thus, the outer shell at least partially covers the frontal bone, parietal bone, occipital bone, opposite sphenoid bones, and opposite temporal bones.

The upper portion 21 may be defined by a minimal surface of the outer shell extending from its top (upper end), when the helmet is worn normally, with the head upright, to a curve defined by the intersection between the outer shell and a plane offset downwardly by a distance D of about thirty millimeters in relation to the top. This distance D may vary between twenty-five and forty millimeters.

In the illustrated example, the upper portion extends beyond this minimal surface.

The upper portion 21 provides protection against puncture and participates in damping impacts.

The lower portion 22 provides adequate protection for the lower zones of the skull. It also limits the deformation of the outer shell 2 during lateral impacts by providing rigidity and strength to the helmet.

In a horizontal cross section in the area of the wearer's ears, the lower portion 22 has a U-shape extending behind the skull.

In a non-illustrated embodiment, the lower portion 22 can be formed to surround the skull. In such a case, the previously defined lower portion 22 extends towards the front of the helmet, and then covers a front portion of the frontal bone. The lower portion 22 thus forms a ring which further rigidifies the outer shell 2. Consequently, the helmet has greater strength when biased laterally.

The lower portion 22 of the outer shell 2 extends continuously over a width advantageously at least equal to twenty millimeters so as to connect the opposite sphenoid bones, passing by the occipital bone. This width, for example, is between twenty and seventy millimeters on this zone.

The lower portion 22 is affixed to the upper portion 21. The lower portion 22 and upper portion 21 are formed of materials having different moduli of elasticity. With such a configuration, the lower portion 22 ensures satisfactory protection of the zones that it covers while rigidifying the outer shell 2 through its attachment to the upper portion 21. This rigidity provides strength to the helmet and prevents collapsing of the upper portion 21 connected thereto. The attachment to the upper portion 21 promotes the impact resistance of the outer shell 2.

In the illustrated embodiment, the lower portion 22 of the shell 2 is continuously attached to the upper portion 21, starting from one sphenoid bone to the opposite sphenoid bone, passing by the occipital bone. The upper portion and lower portion thus form a single unitary piece, that is, an integrated or unified structure. Structural cohesiveness is thus promoted between the upper 21 and lower 22 portions, and therefore a better mechanical grip between the two portions. An overmolding or bi-injection process can be used to obtain this unitary or unified outer shell, as described in greater detail below. The helmet thus includes an overmolded or bi-injected outer shell, thereby providing it with optimized characteristics to meet the standards of the intended discipline.

In an alternative embodiment, the two elements can be detachable from one another, thereby making it possible to replace one portion with another one having different mechanical properties, or if the replaced portion is damaged.

For a helmet 1 designed for alpine skiing or snowboarding, the upper portion 21 is formed of a material having mechanical properties promoting puncture resistance, whereas the lower portion 22 is formed of a material having a higher modulus of elasticity, in order to promote rigidity and resistance to impacts.

Furthermore, the impact damping characteristics at the top of the helmet generally determine the dimensions for the helmets. They are mainly determined by the mechanical properties of the cap. However, the outer shell also has a bearing on the damping properties of the helmet. In most the existing helmets, the outer shell is made of a single material and is very rigid, in particular in the first protection zone. This rigidity penalizes the damping ability of the helmet for vertical impacts. A helmet of the invention, designed for use in the alpine ski discipline, uses a more flexible material, at least in the area of the first protection zone 211. By being more flexible, the outer shell absorbs a portion of the vertical impact. Moreover, by being connected to a more rigid lower portion, the upper portion can buckle to damp the vertical impact.

To obtain good performance from the helmet, and in particular good damping, the upper portion 21 is made of a flexible material having a modulus of elasticity or Young's modulus between 100 and 1000 MPa. One can consider the tensile stress at 100% elongation to characterize a flexible material. For this upper portion, the stress can be in the range between 20 and 50 MPa. The Shore D hardness of the material is advantageously between 50 and 75. It can be PU (Polyurethane), PP (polypropylene), SBS (Styrene-Butadiene-Styrene), or SEBS (Styrene-Ethylene/butylene styrene).

Very good results can be obtained by making the upper portion with Desmopran® DP 9855DU, or IRFRAN® MR 1301-010, or IRFRAN® MR 1301-030.

Advantageously, the wall thickness of the upper portion 21 of the shell 2 is between one and three millimeters.

To provide the helmet with good strength, the lower portion 22 is made of a rigid material having a modulus of elasticity or Young's modulus between 900 and 2500 MPa. It can be PU (Polyurethane), ABS (Acrylonitrile Butadiene Styrene), PP (polypropylene), or PC (Polycarbonate).

Advantageously, the wall thickness of the lower portion 22 of the shell 2 is between one and three millimeters.

To provide the helmet with good damping ability, the modulus of elasticity or Young's modulus of the material forming the lower portion 22 is at least one and a half times greater than that of the material forming the upper portion 21. Advantageously this ratio is greater than two.

The upper portion 21 and lower portion 22 can have the same thickness, of about two millimeters. Alternatively, the upper and lower portions can have different thicknesses, in order to rigidify certain zones.

The average thickness of the outer shell, except for the local excess thicknesses, is less than five millimeters.

The upper portion 21 can be dimensioned to pass the puncture tests of the standard EN 1077: 2007 applicable to alpine ski helmets. A material having sufficient thickness and being sufficiently resilient is used, for example, to form the upper portion 21 of the outer shell 2.

The helmet 1 can be designed to meet certification standards defined for various sports, such as alpine skiing, snowmobiling, mountaineering, or cycling, for example.

Due to the use of two different materials for the upper portion 21 and lower portion 22, the characteristics of the helmet can be designed with respect to the intended activity, while retaining the same helmet geometry. Generally, it suffices to change the upper portion depending on the intended application. For example, for snowmobiling, the resistance to perforation must be reinforced. For climbing, the resistance to projectile impact must be improved. With his/her knowledge, one with ordinary skill in the art can determine which material is most appropriate for the upper portion to satisfy a certification standard defined for a particular use of the helmet. From the standards, he/she may deduct the mechanical properties that should be targeted in selecting the material for the upper portion.

This design makes it possible to consider common tools to make common portions or portions using materials with similar shaping parameters.

In addition, with an outer shell provided with zones made of materials having different mechanical properties, the design can be optimized to locally obtain improved resistance and/or damping, where necessary, while maintaining a lightened structure. The outer shell can also be dimensioned to allow for certification of the helmet in a plurality of disciplines without significantly penalizing the weight. Such a helmet then meets several standards.

The lower portion 22 can be made to comprise a plurality of zones made of different materials, for example in order to locally reinforce the outer shell structure.

There are two main technologies for making a helmet.

A first so-called injection technology involves making the outer shell and the cap separately. Thus, the cap 3 is distinct from the outer shell 2. In a second step, the cap is assembled in the outer shell by suitable connectors such as clips, fasteners, rivets, adhesive, Velcro-type fasteners, etc. This technology offers the possibility of separating the cap of the outer shell when necessary. This can be useful, for example, to replace a damaged portion.

A second so-called thermoforming or “in-mold” technology involves making the outer shell in a first step. In a second step, the shell is positioned inside a mold in which a material is injected to produce the cap. Thus, the cap is directly connected to the outer shell to form a unified element having an average thickness greater than five millimeters. This chemical connection is non-detachable. It provides excellent adhesion between the two portions.

The invention is applicable to helmets made according to the first technology whereby an outer shell is made independently of the cap, the outer shell comprising at least two upper and lower portions made of different materials.

Advantageously, the outer shell is made using an overmolding process or a bi-injection process. These technologies make it possible to obtain a unitary shell. The chemical connection between the upper and lower portions is very good. The shell then has good mechanical hold and requires no or little reworking, thereby enabling an economical finish, adapted for the desired aesthetics.

The overmolding process involves injecting a first portion in advance. This first portion forms an insert which is then positioned in a mold in which the second portion is injected.

The bi-injection process involves simultaneously injecting the two materials in the same mold in order to make the complete shell. This technology makes it possible to obtain a better mechanical and chemical connection between the two portions. However, the cost of the tools is greater than for an overmolding technology.

To properly carry out the injection, it is advantageous for each portion of the shell to have a substantially constant thickness. An excess thickness 24 is provided in the area of the junction area 23 between the two portions to enable the two materials to mix better in order to increase the chemical and mechanical connection between the two portions.

In this example, the junction zone 23 extends over a width of less than thirty millimeters. The thickness of this zone is substantially equal to the sum of the average thicknesses of each assembled portion. Advantageously, it is less than four millimeters in order not to weigh down the helmet.

Advantageously, this excess thickness 24 projects into the inner volume of the outer shell 2. In other words, the excess thickness projects from the inner surface of the outer shell 2 and extends within the shell, in the direction of the user's head when the helmet is worn. Thus, the outer surface of the outer shell is continuous, with no roughness, which is desirable for the aesthetics and aerodynamics of the helmet.

The cap 3 here comprises a groove 31 for receiving the excess thickness 24. Thus, the cooperation between the excess thickness 24 and the groove 31 promotes a relative positioning between the outer shell 2 and the cap 3 during assembly of the helmet 1. In addition, this enables a relative retention between the two elements, this cooperation limiting a relative movement of the cap with respect to the shell. It should be noted that the current helmet designs do not facilitate accurate positioning of the cap in relation to the outer shell.

Furthermore, the excess thickness 24 makes it possible to form a rigidifying strip in the area of the junction between the upper portion 21 and lower portion 22. This rigidity contributes in providing the helmet with good strength and prevents collapsing of the helmet when biased.

In the illustrated embodiment, the cap 3 forms an envelope covering a portion of the skull. This envelope comprises recesses 32 in its internal portion for receiving removable cushions 4. These cushions are fixed to the cap, in the recesses 32, by appropriate fastening expedients, such as an adhesive strip or Velcro-type fasteners, for example. The cushions are deformable, and may be made of foams. These removable cushions can be positioned on the front portion, lateral portions, rear portion, and crown portion of the inner surface of the cap. These cushions are used to improve the wearing comfort by enabling the helmet to be adjusted to the morphology of the user's skull. Thus, by only changing the cushions, the inner interface of the helmet can be adapted to various types of skull morphologies, for example circular/oval skulls. Moreover, being made of suitable materials, cushions can also contribute in damping impacts.

In this example, the helmet is shown with no arrangement for ventilation. The helmet may include such arrangements in the form of openings in the outer shell 2 and air ducts cut into the cap 3.

In the examples, the outer shell is in a single piece, thereby providing a unitary element which is self-supporting and therefore easier to handle.

In an alternative embodiment, the outer shell 2 is produced by overmolding or bi-injection, and the cap 3 is connected to the outer shell by thermoforming, “in-mold” technology. In this case, the cap 3 is continuously affixed to the outer shell 2 and is not removable. This makes it possible to reinforce the cohesion between the elements of the helmet, thereby making the helmet unitary, more solid.

The invention is not limited to these embodiments. Also, it is possible to combine these embodiments.

In addition, rather than being limited to the previously described embodiments, the invention extends to all of the embodiments covered by the appended claims.

Further, at least because the invention is disclosed herein in a manner that enables one to make and use it, by virtue of the disclosure of particular exemplary embodiments of the invention, the invention can be practiced in the absence of any additional element or additional structure that is not specifically disclosed herein. 

1. A helmet for protecting a user's head during participation in at least one of a plurality of sporting activities, said helmet comprising: an outer shell designed to be positioned on a skull, the outer shell including: an upper portion designed to cover at least a crown portion of the skull; the upper portion made of a material having mechanical satisfying properties specified in a certification standard defined for use of the helmet during participation in the at least one of a plurality of sporting activities; and a lower portion affixed to the upper portion so as to form a unified bi-injected or overmolded construction, the lower portion extending continuously so as to at least partially cover the lateral portions and rear portion of the skull, the lower portion being made of a material having a different modulus of elasticity than that of the material forming the upper portion.
 2. A helmet according to claim 1, wherein: the material forming the upper portion has mechanical properties suitable satisfying a certification standard for alpine skiing or snowboarding.
 3. A helmet according to claim 1, wherein: the Shore D hardness of the material forming the upper portion is between 50 and
 75. 4. A helmet according to claim 1, wherein: the modulus of elasticity of the material forming the upper portion is less than 1000 MPa.
 5. A helmet according to claim 1, wherein: the modulus of elasticity of the material forming the upper portion is less than the modulus of elasticity of the material forming the lower portion.
 6. A helmet according to claim 1, wherein: the upper portion is made of one of the following materials: PU, PP, SBS, SEBS.
 7. A helmet according to claim 1, wherein: the lower portion is made of one of the following materials: PU, ABS, PP, PC.
 8. A helmet according to claim 1, wherein: at least one of the upper portion and the lower portion has a wall thickness between one and three millimeters.
 9. A helmet according to claim 1, wherein: the outer shell comprises an excess thickness in an area of a junction zone between the upper portion and the lower portion.
 10. A helmet according to claim 9, wherein: the excess thickness projects into an inner volume of the outer shell.
 11. A helmet according to claim 9, wherein: the excess thickness of the junction zone is substantially equal to the sum of the average thicknesses of each assembly portion.
 12. A helmet according to claim 9, wherein: the junction zone has a width of less than thirty millimeters.
 13. A helmet according to claim 1, further comprising: a cap distinct from the outer shell, the cap being fixed to an inside of the outer shell.
 14. A helmet according to claim 9, further comprising: a cap distinct from the outer shell, the cap being fixed to an inside of the outer shell; the excess thickness being received in a groove arranged in the cap.
 15. A method of manufacturing a helmet according to claim 1, said method comprising: affixing the lower portion to the upper portion to form a unified structure by bi-injecting or overmolding the lower and upper portions together to obtain the outer shell.
 16. A method for manufacturing a helmet for sporting activities, comprising: attaching a lower portion to an upper portion to form on outer shell of the helmet by one of the following: overmolding one of the lower and upper portions to another; bi-material injecting the upper and lower portions. 